function [x_circle,y_circle]=circle(radial,circle_size,x_peak,y_peak)
theta=0;  k=1;     %initial    
x_circle=zeros(circle_size*2+1,1);
y_circle=zeros(circle_size*2+1,1);
while(theta<=2*pi)
      x_circle(k)=round(x_peak+radial*cos(theta));
      y_circle(k)=round(y_peak+radial*sin(theta));
      if x_circle(k)<=1;x_circle(k)=1;end
      if y_circle(k)<=1;y_circle(k)=1;end
      if x_circle(k)>=1023;x_circle(k)=1023;end
      if y_circle(k)>=1023;y_circle(k)=1023;end
      theta=theta+pi/circle_size;
      k=k+1;
end